Historical industrial, commercial, and municipal practices and releases of contaminants dating back to the early 1900s contributed to the observed chemical distribution in sediments within the Swan Island Basin Project Area.

Project areas for in-water cleanup with EPA oversight including Swan Island Basin.

The Portland Harbor Remedial Investigation and Feasibility Study, which was completed in 2015, determined the areas of contamination and risks to ecological and human health in the Portland Harbor Superfund Site, including the Swan Island Basin Project Area.  Risks to human health are from the consumption of resident fish eaten over many (30) years, which could result in an increased cancer risk.

The Record of Decision issued by EPA in 2017 determined the present cleanup plan for the in-water areas of the Portland Harbor Superfund Site.  In its Record of Decision, EPA identified multiple project areas in the Portland Harbor Superfund Site that require cleanup, including the Swan Island Basin Project Area.  

The Remedial Design process is estimated to be completed by 2026. The process entails the development of a detailed cleanup plan and the selection of remedies that may include several technologies (e.g., capping, dredging) to reduce risks from sediment contamination. The Remedial Action (RA) is the actual construction or implementation phase of Superfund cleanup.

Swan Island Basin Remedial Design Timeline

  • 2000EPA lists Portland Harbor on the National Priorities List (Superfund)
  • 2017EPA publishes Record of Decision for the Portland Harbor Superfund Site
  • 2021EPA approves an Agreement on Consent for Swan Island Basin Remedial Design
  • 2022-2023Swan Island Basin Remedial Design Group collected 2,448 samples of sediment, riverbank soil, stormwater, and other environmental media to inform Remedial Design.
  • 2022-2026EPA oversight of Remedial Design
  • After 2026EPA to identify who will perform Remedial Action and start cleanup activities

Current work

Under construction at this time.